GABAergic neurons are a prominent class of neurons whose dysfunction can results in various disease states. The developmental mechanisms that result in terminal differentiation of GABAergic neurons and the functional properties of many GABAergic neurons are incompletely understood. We propose here to use the experimental advantages of the nematode C.elegans to decipher the gene regulatory events - both on the level of cis-regulatory elements and trans-acting factors - that induce the expression of terminal identity markers of a single GABAergic interneuron (Aim #1) and we propose to study a potential role of this GABAergic interneuron in controlling metabolic states and life span of C. elegans (Aim #2).